Flexible tubing



NOV. 20, 1923.

A. SUNDH FLEXI BLE TUBING Filed Dec. 20 1919 INVENTOR AT ORNEYS-Patented Nov. Zfl, F1923.

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AUGUST SUNDH, 01F HASTINGS-ON-HUDiSON, YORK.

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Apol'lcation filed. December 20, 1919. Serial No. 364,29t5.

To all whom it may concern: Be it known that 1, AUGUST SUNDH, a citi-'--zen of the United States, and a resident of Hastings-on-Hudson, inthe county of Westch'ester and State of New York, have invented certainnew and useful Improvements in Flexible Tubing, of which the following'is a specification.

My invention relates to flexible, metallic tubing constructed ofcorrugated, metal strips helically wound to form a corrugated, flexible,metallic tube.

In the, present invention I have provided an inner, metallic membercomprising a helically wound, corrugated, metal strip which when woundforms a metal tube having inwardly and outwardly extending loops. llenvelop this member in a helically wound, metal strip which when woundalso forms a corrugated tube having inwardly and outl. wardly extendingloops. The adjacent edges of the strips are attached to each other bysolder which may be fused as the tubing is.

being formed or applied in any other suitable way, and also the loops ofthetwo membars are secured to each other at all points by solder orother fusible, metallic binder. In the accompanying drawings, Fig. 1 isa part sectional elevation of an embodiment of my invention;

Fig. 2 is an enlarged, sectional, elevational view of the tubing of Fig.1; and

Fig. 3 shows diagrammatically a modifi-.

cation of the tubing of Figs. 1 and 2. Referring to the drawings indetail, 1 designates ,3. corrugated, metal strip helically wound to-form inwardly extending,

loops 2 and outwardly extending loops 3. Enveloping the strip'l is ahelically wound, metal strip 4, this strip be ng corrugated and wound tofotm outwardly extending loops 5 and inwardly extending loops 6.

The adjacent edges of the helically woundstrip 1 approach each other atthe point 7 which is beneath the base of the inwardly extending loops 6of the outer strip 4. The adjacent edges of the outer strip approacheach other at the point 8, immediately above the outwardly extendingloops 3 of the inner member. The inwardly and outwardly extending loopsof the two members 1 and 4 are shaped so as to conform to each other andare secured to each other at'every point by a fusible,metallic binder 9such assolder fused during the forming of the tube, this binderc'tioning not only to secure the two strips to, each other but also tosecure the adjacent edges of each strip to each other at the points 7and 8.

Other methods of securing these strips to each other may be employedsuch as, for example, .coating the surfaces of each strip to be joinedwith solder, then bringing the two strips together and applying heat tofuse the solder, thereby securely joining the two strips to each otherat all points to form a unitary flexible tubing.

In the embodiment of my invention illus trated in Fig. 3 l have showndiagrammatically a. flexible tubing comprising an inner flexible,metallic strip 10 helically wound to form inwardly and outwardlyextending loops 11 and 12, respectively. This strip 10 is enveloped by ahelically wound, metal strip 13 having inwardly and outwardly ex tendingloops 14: and 15, respectively. En-

veloping the strips 11 and 13 is a helically wound, metal strip 16having inwardly extending loops 1'? and outwardly extending loops 18.The inwardly and outwardly extending loops of all three members aresecured to each other at all points by a fusible, metallic binder suchas solder as in the case of the tubing of Fig. 1. llt will be noticedthat the adjacent edges of the inner strip 11 approach each other at thepoint 19; the adjacent edges of the strip 13 approach each other at thepoint 20' which is in a different part of theloops of the tubing as awhole; and that the adjacent edges of the strip 16 app-roach each otherat the point 20 at the base of the inwardly extending loops. @In otherwords, the pointsof approach of the adjacent edges ofthe strips arestaggered so as not to weaken the tubmg. I

It'will be seen from the foregoing that I have provided what may beconsidered as a double-walled, flexible, metallic tubing, thecorrugations or inwardly and outwardly extending loops of each wallbeing secured to each other at all points by means of fusible, metallicbinder whereby leakage of the tubing, due to leaky joints, iseliminated, the flexibility of the tubing, however, being maintained.

I am aware that flexible tubing has been made by merely corrugating ametal tube or vmetallic binder for securing the loops of both members toeach other extending to all points of theloops.

What I claim asnew is:

1. The method of making a flexible II18-' tallic tubing consisting inhelically winding a corrugated metal strip to form a tube havinginwardly and outwardly extending loops, Winding a second corrugatedmetal strip about the first strip so as to bring the inwardly andoutwardly extending loops of the one strip in register with the similarloops of the other strip to form a double walled tube, and permanentlyand rigidly uniting the face of the inner strip to the a jacentoverlying face of the outer strip throughout their entirety.

2. A flexible metallic tubing comprising navaeie a metal tube composedof a helically wound corrugated metallic strip surrounded by acorrugated metal strip wound helically so that the loops thereofregister with the loops formed by the corrugations on the inner tube,the two strips being permanently united to each other throughout theirentire length. v

3. A flexible, metallic tubing comprising a corrugated metal striphelically wound to form inwardly and outwardly extending loops, theadjacent edges of said strip approaching each other at the base of theinwardly extending loops, a helically wound, corrugated, metal stripenveloping thefirstnamed strip and having inwardly and outwardlyextending loops, the adjacent edges of the enveloping strip approachingeach other at the base of the outwardly extending loops of said strip,and a fusible binder between adjacent edges of both strips and betweenthe walls of th inner member and the enveloping member'for binding thetwo metal strips to each other at all points and to prevent separationof the adjacent edges of each strip.

This specification signed this 17 day of December, 1919.

AUGUST SUNDH.

